Refrigerating system with continuous integral closed circuit refrigerantconducting tubing



' May 1-9, 13964 R. w. KRITZER 3,133,430

REFRIGERATING SYSTEM WITH CONTINUOUS INTEGRAL CLOSED CIRCUIT REFRIGERANT-CONDUCTING TUBING Filed Jan. 17, 1963 EV/IPO 470A 15206225397" M2 4 W x i 1 55762 Richard W. Kritzer,

United W States Patent 3133 430 nnrrncnnAriNc sYsTEir WITH CoNTINUoUS INTEGRAL CLOSED crncurr REFRIGERANT- coNnucrrNn TUBING Filed Jan. 17, 1963, Ser. No. 252,178 1 Claim. (Cl. 62-5ll3) The improved refrigerating system comprising the pres ent invention has been designed for use primarily in connection with electrically powered household equipment such as a refrigerator, a low temperature freezing unit, an air conditioner or the like. The invention is, however, applicable to other equipment such, for example, as a refrigerating system for a commercial ice-making machine, an air liquefaction system, a shipboard refrigerating system, a system such as is employed in connection with a railway or motor vehicle refrigerator car or truck, an air conditioning system in a passenger vehicle, and other systems too numerous to mention. Irrespective, however, of the particular use to which the invention may be put, the essential features thereof are at all times preserved.

The invention is specifically applicable to a refrigerating system of the compressor-condenser-evaporator type, such a system embodying, basically or fundamentally, a closed circuit liquid-gas path of travel for a particular refrigerant, the refrigerant vapor being compressed in the cylinder of a power-driven compressor and then passing in a compressed state to the coils of a heat exchange type condenser where heat is extracted therefrom. From the condenser coils the refrigerant in a liquefiedcondition is caused to pass through a restriction (usually an expansion valve or a capillary tube of small diameter) in order that upon expansion thereof at the downstream side of the restriction it evaporates. After flow through the restriction the refrigerant passes through the coils of an evaporator where cooling takes place almost instantaneously due to the phenomena of both evaporation and expansion of the refrigerant. The evaporator being in the form of a heat exchange device, absorbs heat from the surrounding air in the case of an 'air conditioner or refrigerator, or' hrine in the case of an ice-making machine, and the vaporized refrigerant, after performing its useful heat-absorbing function, returns to the compressor and the process is repeated indefinitely. In many instances, such as in a household refrigerator, the system includes an accumulator in the closed circuit refrigerant path, this accumulator being merely a volumetric enlargement which is disposed in the confining path of vapor flow between the evaporator coils and the compressor and functions to prevent liquid refrigerant from entering the compressor and also functions as a stabilization chamber and surge tank for the refrigerant.

Heretofore, the condenser, the restriotionforming device, the evaporator and the accumulator have been manufactured as entirely separate or independent units and the tubing which is associated with each unit has been either welded together to provide the closed refrigerant system or operatively connected together by suitable threaded fittings or the like during assembly of the refrigerating system. Where the restriction-forming device is in the form of a capillary tube, its diameter must be appreciably smaller than the diameter of the tubing between the condenser and the evaporator and the ends of the capillary tube must be sealed to the adjacent end posi- 13 55 N. Astor St., Chicago 11, ill.

tions of the tubing between the condenser and the evaporator. Additionally, the accumulator inlet opening must be sealed to the outlet end of the evaporator tubing, .while the outlet opening of the accumulator must be sealed to the length of tubing which leads to the inlet side of the compressor. The various sealing means regardless of whethter they are formed by welding or by reduction fittings are a source of possible refrigerant leaks in the system and, furthermore, they involve costly assembly operations from the standpoint of labor and materials.

According to the present invention, it is contemplated that the capillary tube and the accumulator instead of being in the form ofseparate entities or units, be constructed from tubing stock and that, moreover, the capillary tube and the accumulator together with the tubing lengths which make up the tubing for the condenser and the evaporator be formed as an integral whole from a single or one-piece length of tithing stock and that the opposite open ends of such one-piece length of tubing stock be operatively connected to the inlet and outlet sides of the compressor. By such an arrangement, and in the absence of welds or reduction fittings between the various tubing lengths, numerous sources of possible refrigerant leaks are eliminated while at the same time labor costs in the formation of the refrigerating system as a whole are reduced to a minimum.

The provision of such a refrigerating system being among the principal objects of the invention, numerous other objects and advantages of the invention will become readily apparent as the following detailed description ensues.

In the accompanying single sheet of drawings forming a part of this specification, there is illustrated one embodiment of the invention in the form of a refrigerating system employing the integral or one-piece tubing feature.

" iIn these'drawings:

FIG. 1 is a perspective view, somewhat schematic in its representation, of a refrigerating system embodying the integral tubing of the present invention; and

FIG. 2 is a side elevational view, likewise schematic in its reprwentation, of the tubing prior to its deformation and assembly in the system.

Referring now to the drawings in detail and in particular to FIG. 1, the refrigenation system which is illustrated schematically therein is designated in its entirety by the reference ntuneral 10. Functionally, the system 10 is. of the conventional compressor-condenserevaporator type, including as it does a compressor 12, a condenser .14 and an evaporator 16. As will be described in greater detail presently, the compressor 12, the condenser 14 and the evaporator 16 are operatively connected together in series relationship by means of a closed refrigerant circuit which is defined by a single one-piece length of tubing 20 and is adapted to contain a suitable refrigerant such as sulphur dioxide, ethyl chloride or any suitable comend of the single length of tubing is connected to the inlet side 22 of the compressor 12 and the other end of the tubing length is connected to the discharge side 24 of the compressor.

The condenser 14 is preferably, but not necessarily, of the finned tubing type and includes a serpentine section 26 of the tubing 20. The straight reaches of the serpentine section 26 are equipped with a cluster of spaced apart, fiat fins 28 for heat dissipating purposes. The section 26 constitutes the so-called condenser coil which is ordinarily associated with a refrigerated condenser.

The evaporator 16 is likewise preferably of the finned tubing type and includes a serpentine section 30 of the tubing 20. The straight reaches of the section 36 are provided with a cluster of spaced apart, fiat fins 32. The serpentine section 50 constitutes the so-called' evaporator coil which is associated with a refrigerant evaporator.

At a region between the condenser 14 and the evaporator 16, and in the path of flow of the liquefied refrigerant from the former to the latter, a short length 34 of the tubing 2i) is reduced or restricted to capillary size and provides the usual expansion orifice (restriction) which releases the compressed refrigerant in vaporized form for flow to the evaporator.

At a region between the evaporator 16 and the inlet side 22 of the compressor 12, a length 36 of the tubing 20 is increased in diameter to provide an accumulator having a volumetric capacity commensurate with the desired overall quantity of refrigerant in the system. The accumulator in addition to serving its function as a storage reservoir for the refrigerant in the system, also functions as a surge tank for pressure equalization in the system.

From the above description it will be observed that the single length of tubing 20 involves five sections which are variously fabricated or formed on three different diameters. Extending sequentially from the discharge side 24 of the compressor 12, to the inlet or suction side 22 thereof, these five sections consist of a first section which'embodies the serpentine section and a short section 40 leading from the discharge side 24 of the compressor 12, and is of a given intermediate diameter, a second section which embodies the short tubing length 34 for capillary tube forming purposes and with the exception of tubing length 34 is of the same diameter as the first section, a third section which embodies the serpentine section and is of the intermediate diameter, a fourth section which embodies the accumulator 36 of materially increased diameter, and a fifth section which embodies that portion 42. of the tubing 20 which leads from the discharge end or opening of the accumulator to the inlet or suction side 22 of the compressor 12. The tubing 29 is devoid of scams or joints in that it embodies no threaded fittings, couplings or welded connections except for such inlet and outlet fittings as may be required for connection of the ends of the tubing to the inlet and outlet sides 22 and 24 of the compressor.

The method by means of which the tubing 20 is formed on three different diameters forms no part of the present invention and various methods are contemplated. Likewise, the tube bending operations which must be performed upon the tubing to secure proper placement of the various components in the final refrigerating system may be accomplished in several ways. It is possible by the localized application of heat to the original length of tube stock and by the application of relatively high internal pressure to the tubing to expand the tubing from the intermediate diameter of the condenser and evaporator sections 26 and 30 to the large diameter which is required by the accumulator tubing length 36. An encompassing mold may be employed to limit the size and shape of the completed accumulator. Likewise, by the application of localized heat and the use of external shrinking dies, it is possible to shrink the tubing 26 from its original intermediate diameter to the reduced diameter which is required by the capillary tube forming lengths 34. It is also possible to expand the tubing from its intermediate diameter to the large diameter of the accumulator by the use of internal expanding mandrels inasmuch as the accumulator occurs at a region not far removed from one end of the tubing and, consequently, a relatively short length mandrel will sufiice for the operation. If desired, the expanding and shrinking operations may be performed before tube bending operations are resorted to. However, in the formation of the specific tubing shape which is represented by the tubing 20 of the system of FIG. 1, in the interests of space conservation in the operating area of the manufacturing plant, it is most expedient first to bend the tubing to produce the two serpentine sections 26 and 30 in coplanar relationship as shown in FIG. 2, and thereafter the expanding and shrinking operations to provide the accumulator and capillary tubing lengths 36 and 34 may be resorted to. After such localized expanding and shrinking operations have been effected as indicated in dotted lines in FIG. 2, the necessary right angle and other bends may be effected in the tubing 20 to bring the serpentine sections 26 and 30 into parallelism and otherwise create the finished tubing contour. For the various bending operations which are involved, an apparatus similar to that which has been shown and described in copending United States patent application Serial No. 214,972, filed on August 6, 1962 by Richard W. Kritzer, Jr., and entitled Apparatus for Eifecting Reverse Bends in Dual Heat Exchange Tubing, is available and is capable of conveniently, and without requiring an inordinate amount of operating space, performing all of the necessary bending operations to shape the locally expanded and shrunk tubing to the final required shape. As a final step, the application of the fins 28 and 32 to the serpentine sections 26 and 36 may be effected.

The invention is not to be limited to the specific tubing contour which has been illustrated in FIG. 1 since, if desired, the various tubing sections or lengths 26, 40; 34; 3t); 36; and 42, may assume different relative orientation from that illustrated. Whatever the relative orientation of these tubing sections, the essential feature of the invention, namely the integral formation of the sections to produce for the refrigerant a continuous closed circuit flow path which is devoid of mechanical or welded joints, is at all times preserved.

The invention is not to be limited to the exact arrangement of parts shown in the accompanying drawings or described in this specification as various changes in the details of construction may be resorted to without departing from the spirit of the invention. Only insofar as the invention has particularly been pointed out in the accompanying claim is the same to be limited.

Having thus described the invention what I claim as new and desire to secure by Letters Patent is:

In a refrigerating system of the compressor-condenscr evaporator type, a compressor having an inlet side and a discharge side, a condenser including a condenser coil, an evaporator including an evaporator coil, means defining a closed-circuit path of flow for a refrigerant fluid from the discharge side of the compressor through the condenser coil and the evaporator coil to the inlet side of the compressor, said means comprising a single length of tubing, devoid of seams and joints, and having its ends operatively connected to the inlet and the discharge sides respectively of the compressor and including first and second medial sections, each of which is bent into serpentine form so as to have straight reach portions and communicating reverse bends, said first medial section constituting the condenser coil, said second medial section constituting the evaporator coil, a plurality of flat, spaced apart fins operatively secured to the reach portions of each medial section, a length of tubing which extends between the condenser coil and the evaporator coil being reduced in diameter throughout its entire length to uniform capillary size in order to provide an expansion orifice for releasing compressed refrigerant for flow to the evaporator c011, a length of the tubing which extends from the evaporator coil to the inlet side of the compressor being of increased diameter in order to provide a refrigerant accumulator section for refrigerant storage and stabilizing purposes.

References Cited in the file of this patent UNITED STATES PATENTS Litle Apr. 20, Summers Apr. 28, White July 18, Shawhan Mar. 25, Gould May 17, Abbott Aug. 30, 

